sx_eval now accepts files (smart-loaded by mtime — unchanged files skip),
trace_io (harness-wrapped IO capture), mock (evaluated platform overrides),
and setup params. Definitions survive between calls. sx_harness_eval also
uses smart loading. sx_write_file can create new files.
New lib/hyperscript/debug.sx: mock DOM platform for instant hyperscript
testing — compile and execute HS expressions against simulated elements,
see every DOM mutation and wait in the IO trace.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
